1. Field of the Invention
The present invention relates to a pad for use in an air bag device installed in an automobile and enclosing an air bag that inflates in case of an accident.
2. Description of the Prior Art
A conventional pad of this kind is shaped like a box, and comprises an upper wall and side walls extending downward from the fringes of the upper walls. The pad consists mainly of a soft synthetic resin, and the upper wall has a thin-walled portion to permit the upper wall to break at a given position, in order that the air bag can be thrown out of the pad and inflate greatly over the pad in case of an accident.
Also in the conventional pad of this kind, flexible meshy nets are embedded in the upper wall and in the side walls except for the thin-walled portion to prevent the pad from breaking and becoming scattered about when the air bag swells. Further, an annular band which is made from aramid fiber or other material exhibiting a high tear resistance is seamed to the nets near the bottoms of the side walls of the pad (see Japanese Patent Laid-Open No. 110643/1980, U.S. Pat. No. 4,334,699)
In fabricating the pad as described above, if the nets and the band which have been seamed together are disposed between inside and outside coat layers of a soft synthetic resin, and if these coat layers are manufactured separately, then a large number of manufacturing steps are needed.
Preferably, therefore, the nets to which the band has been seamed is used as an insert that is set afloat by engaging a number of set pins protruding from the inner surface of a mold, for forming the coat layers.
However, when the insert is placed in position, it is necessary that it assume a box-like form substantially conforming to the shape of the pad while set afloat over the surface of the mold. Since the nets and the band constituting the insert are made from a flexible material, the insert bends easily. For this reason, it is cumbersome to set the insert in position.